Means for making pulleys

ABSTRACT

An apparatus and method are provided for forming a pulley including a pulley groove from a cup-shaped metal blank having an axially extending wall. The blank is crushed between axially closing dies which are used in combination with forming rolls arranged to apply radially inwardly directed rolling pressure to the wall of the blank. The forming rolls include rough and finish rolls which are carried by cam actuated slide assemblies arranged to move the rough roll into the blank wall in advance of the finish roll in a working operation so as to partially form a pulley groove and to maintain the finish roll in the partially formed groove in an idling operation. Thereafter, the rough roll is disengaged from within the partially formed pulley groove and the finish roll is advanced to the root of the partially formed groove and into a working operation. The axially closing die movement includes a lost motion dwell during which the dies are moved as a unit in their final relative position together with the finish roll to assure the complete radial advance of the finish roll to assure the complete radial advance of the finish roll and the truing of the pulley being formed.

United States Patent [191 Haswell et al,

[11] 3,831,414 Aug. 27, 1974 MEANS FOR MAKlNG PULLEYS lnventors: John W. Haswell; Stanley A.

Haswell, both of c/o Master Craft Engineering, Inc., 39555 Express Hwy, Belleville, Mich. 48111 Filed: July 9, 1973 Appl. No.: 377,643

References Cited UNITED STATES PATENTS 10/ 1931 Harrison 72/82 3/1958 Wickwire et al.... 29/159 R l/l959 Killian et a1 29/159 R 4/1972 Zatko 72/82 Primary Examiner-Richard J. Herbst Attorney, Agent, or Firm-McNenny, Farrington, Peame & Gordon [57] ABSTRACT An apparatus and method are provided for forming a pulley including a pulley groove from a cup-shaped metal blank having an axially extending wall. The blank is crushed between axially closing dies which are used in combination with forming rolls arranged to apply radially inwardly directed rolling pressure to the wall of the blank. The forming rolls include rough and finish rolls which are carried by cam actuated slide assemblies arranged to move the rough roll into the blank wall in advance of the finish roll in a working operation so as to partially form a pulley groove and to maintain the finish roll in the partially formed groove in an idling operation. Thereafter, the rough roll is disengaged from within the partially formed pulley groove and the finish roll is advanced to the root of the partially formed groove and into a working operation. The axially closing die movement includes a lost motion dwell during which the dies are moved as a unit in their final relative position together with the finish roll to assure the complete radial advance of the finish roll to assure the complete radial advance of the finish roll and the truing of the pulley being formed.

15 Claims, 9 Drawing Figures PATENIED 2 7 i574 simsnrs MEANS FOR MAKING PULLEYS BACKGROUND OF THE INVENTION The present invention relates to the provision of single or multiple V-groove pulleys which are formed from blanks in the form of metal cups having a closed end and a cylindrical wall extending therefrom. The blank is crushed between axially movable die members which cooperate with relatively rotating rough and finish forming rolls to radially, inwardly deform and axially collapse the blank to form the pulley. In their fully closed position or final apposition, the axially movable die members cooperate with the finish roll to define a die cavity corresponding to the pulley being formed.

In accordance with the prior art, the rough and finish rolls are sequentially advanced into working engagement with the blank from their respective, fully retracted positions. Consequently, it is necessary to expend a substantial amount of cycle time in the pulley forming operation moving the rough and finish forming rolls into and out of working engagement with the blank.

The uniformity of blank deformation is a function of cooperative axial and radial loads applied thereto during the pulley forming operation. Upon the interchange of the rough and finish rolls in accordance with prior art techniques, the blank is solely subjected to axial loading for a relatively significant period of time unless the axial closing movement of the die members is also interrupted. In the absence of such an interruption, the axial collapse of the blank may be circumferentially irregular as a result of variations in the thickness of the blank wall. If an irregular collapse occurs, the balance and concentricity of the resulting pulley will be adversely affected. These adverse effects may be remedied in the finish roll forming operation but only at the expense of working and stressing the metalof the blank wall to a relatively greater degree.

It is believed that the foregoing forming roll inter change" problems are alleviated to some extent by the relatively slow closing movement of the axially movable die members which has heretofore characterized prior art pulley forming operations of this type. More particularly, the axial closing movement of the dies is slow enough to substantially reduce the relative amount of axial deformation and metal flow which occurs during the period of interchange. Of course, the relatively slow closing movement also results in an increased overall cycle time during which the finish roll works within the pulley groove being formed to eliminate eccentricity. The obvious disadvantages of this prior art technique include a long cycle time and correspondingly low production rates.

SUMMARY OF THE INVENTION The present invention provides an apparatus and method for forming a pulley including at least one pulley groove from a cup shaped metal blank having a cylindrical sidewall. The apparatus may be installed in a conventional press to form pulleys in accordance with the method of the present invention. The apparatus includes opposed, axially movable die members for applying axial pressure to the blank and roll die means for simultaneously applying radially inwardly directed, rolling pressure around the circumference of the cylindrical sidewall of the blank. The die members and roll die means thereby cooperate to form a groove having the desired root diameter connected to outwardly flaring wall portions which are axially crushed together by the die members in their closed position to provide the pulley groove with its ultimate cross sectional configuration.

In the illustrated embodiment, the roll die means comprise first and second forming rolls arranged for simultaneous movement towards the longitudinal axis of the blank. The forming rolls remain in contact with the blank until their respective working operations are completed.

The first forming roll is moved slightly in advance of the second to deform the sidewall of the blank in a working operation and partially form the pulley groove while the second forming roll is disposed within the partially formed groove in an idling operation. At the completion of its working operation, the first forming roll is disengaged from the partially formed pulley groove and the second forming roll is substantially simultaneously moved into a working operation with a negligible amount of non-working, radial travel. The second forming roll is then continuously advanced to an imaginary circle having a diameter equal to the desired root diameter of the pulley groove to cooperate with the movable die members at their final apposition to completely define the cross section of the pulley being formed.

The forming rolls are carried by associated slide assemblies which are cam actuated to provide movement thereof towards the longitudinal axis of the pulley blank. The camming actuation is provided by cam arms arranged for corresponding, parallel movement with the closing action of the axially movable die members. The slide assemblies are resiliently biased against the cam actuation and upon completion of the camming movement, the assemblies return to retracted, laterally spaced positions relative to the axially movable die members.

Each of the forming rolls is resiliently mounted on a shaft carried by its associated slide assembly to provide relative axial movement of the forming rolls to accommodate metal flow of the blank during the pulley forming operation. Accordingly, the first forming roll is axially displaced during the formation of the pulley groove in accordance with the closing of the axially moving members, and the second forming roll is similarly displaced since it is captured within the pulley groove being formed. In this manner, the apparatus of the present invention provides simultaneous displacement of the forming rolls toward the longitudinal axis of the pulley blank as well as the appropriate axial displacement of the forming rolls to assure their disposition within the pulley groove being formed.

In constrast with the prior art teachings, the present invention enables the forming operations of the rolls to be provided in a substantially continuous manner. More particularly, the pulley forming process is not interrupted by the disengagement of the first forming roll and the movement of the second forming roll into the partially formed pulley groove from its fully retracted position. In addition, the transition from the first to the second forming roll operation is essentially simultaneous and one or the other of the fonning rolls is substantially continuously cooperating with the die members to assure the uniform deformation of the blank.

The closing movement of the axially movable members includes a dwell period during which both of the members as well as the blank are translated in the same direction in their final forming position together with the second forming roll. During the dwell period, the second forming roll travels within the groove performing a truing operation to assure the balance and concentricity of the pulley.

It should be appreciated that the dwell is achieved without interrupting the rate at which the movable dies are axially travelling but rather by the provision of a limited amount of lost motion. It has been found that the provision of such a dwell eliminates the necessity of precisely synchronizing the movement of the axially movable members and the roll die means to assure their simultaneous disposition at their final apposition. Consequently, the rate at which the movable dies are brought together has been greatly increased and the overall cycle time to form a pulley has been correspondingly decreased.

The reduction in cycle time resulting from the increase in the closing rate of the movable die members and the substantially simultaneous transition from the rough to finish roll forming operations have essentially converted the pulley forming technique in accordance with the present invention to a punch press-like operation. For example, production rates on the order of S pulleys per hour have been achieved in accordance with the teachings of the present invention.

The apparatus of the present invention may be installed in a conventional press as a unitary package in order to convert the press into a pulley forming machine. The apparatus is arranged to utilize the closing movement of the press to precisely position and drive the forming rolls throughout the pulley forming operation. The movement of the forming rolls is readily synchronized with that of the axially movable die members by a direct camming action provided by the closing press movement. Accordingly, the blank is axially and radially loaded in a uniform and accurate manner by virtue of the singular, closing movement of the press and synchronization of independent controls for the axially movable die members and forming rolls is eliminated. Further, the provision of the lost motion dwell obviates the necessity of precisely synchronizing the arrival of the die members and finish roll at their final apposition and facilitates the truing operation of the finish roll.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front elevational view partially in section of a press having a pulley forming apparatus including rough and finish forming rolls and a pulley blank disposed therein according to the present invention;

FIG. 2 is an elevational view on an enlarged scale of the pulley forming apparatus shown in FIG. 1 with parts broken away and omitted for purposes of illustration;

FIG. 3 is a cross sectional plan view of the apparatus illustrated in FIG. 2, the plane of the view being indicated by the line 3--3 in FIG. 2;

FIG. 4 is a diagrammatic cross sectional view of the apparatus shown in FIG. 2 illustrating the initial stages of the pulley forming operation;

FIG. 5 is a diagrammatic cross sectional view similar to FIG. 4 illustrating the apparatus just after the disengagement of the rough forming roll;

FIG. 5a is an enlarged cross sectional view of a portion of FIG. 5 illustrating the engagement of the finish forming roll with the partially formed pulley groove;

FIG. 6 is a diagrammatic cross sectional view similar to FIG. 5 illustrating the apparatus just prior to the completion of the pulley forming operation;

FIG. 6a is an enlarged cross sectional view of a portion of FIG. 6 illustrating the engagement between the finish forming roll and the completely formed pulley groove; and

FIG. 7 is a front elevational view similar to FIG. 1 illustrating the press and apparatus at the completion of the pulley forming operation.

DETAILED DESCRIPTION OF THE DRAWINGS Referring to FIG. 1, a press 10 having a pulley forming apparatus 12 mounted therein in accordance with the present invention is illustrated. The press 10 is a conventional punch press including a frame structure 14, an axially reciprocal ram 15 having a ram plate 16 fixed thereto and a fixed lower bed or bolster plate 18. The press is shown in an open or loading and unloading position with the ram 15 retracted and a pulley blank 20 positioned within the pulley forming apparatus.

The pulley forming apparatus 12 is mounted between the plates 16 and 18 of the press for axially closing movement therewith. Accordingly, the apparatus includes an upper platen 22 which is rigidly fixed to the ram plate 16 and a lower platen 24 which is captively connected to the bolster plate 18 by axially projecting, overhanging arms 18a and 18b. The arms 18a and 18b extend respectively along the opposed lateral sides of the platen 24 and permit a limited amount of axial movement of the platen to provide a lost motion dwell as indicated in greater detail below.

When the press and pulley forming apparatus are in the open or loading position as shown in FIG. 1, the lower platen 24 is maintained in a raised position against the overhanging edges of the arms 18a and 18b. The lower platen is resiliently biased to its raised position by support rods 26 extending from an air spring 28 fixed to the frame 14 of the press. The support rods are provided in aligned pairs (only one member of each pair is shown in FIG. 1) to uniformly support and resiliently bias the lower platen 24 to is axially spaced position relative to the upper surface of the bolster plate.

The use of an air spring mounting system is particularly advantageous since the air pressure may be adjusted to provide different spring rates to accommodate various pulley wall gauges and sizes. However, compression springs (not shown) or other resilient mounting means can be employed in the apparatus to provide the axially, yielding movement of the lower platen 24 after the biasing force of the springs or resilient mounting means has been overcome by the ram pressure.

Referring to FIGS. 2 and 3, the pulley blank 20 is pre formed and provided with a cup shape. The blank is formed of metal and it has a closed concave end 30, an axially extending, cylindrical sidewall 32 and an opposed open end defined by the terminating edge 34 of the sidewall. A centrally located axial bore 36 extends through the closed end 30 of the blank adjacent the longitudinal axis A thereof. It should be appreciated that the blank may be provided with a variety of different configurations and that it may include a braised hub (not shown) adjacent the axial bore.

The pulley forming apparatus 12 includes axially movable members 38 and 40 which are respectively secured to the upper platen 22 and lower platen 24. The members 38 and 40 are arranged for closing axial movement upon advance of the upper platen toward the lower platen along guide posts 42. Of course, either or both of the platens may be arranged for movement toward one another in order to close the members 38 and 40.

The members 38 and 40 are respectively provided with an upper die member 44 which includes an associated die pad 46 and a lower die member 48 which includes an associated die pad 50. Upon movement of the members 38, 40 to their closed, final apposition, the die members cooperate to define a die cavity corresponding to portions of the pulley to be formed.

As shown with respect to the lower axially movable member 40, the die members are detachably connected by means of adapter plates, such as adapter plate 52. Accordingly, various dies may be employed to provide pulleys having corresponding configurations.

In order to assure the proper positioning of the blank in the apparatus, the lower die pad 50 is provided with a pilot pin 54 which extends through the axial bore 36 of the blank 20. The upper die pad 46 has an axially extending bore 56 which receives the pilot pin upon closure of the dies.

The members 38, 40 are axially aligned and mounted for rotation about their common longitudinal axis which corresponds with the axis A of the blank and the pulley to be formed. In addition, one or both (preferably one) of the members 38, 40 may be arranged to be driven in order to establish rotative movement about the axis A. For example, the member 40 may be rotatively driven by a splined drive shaft (not shown) provided by the press and extending through the lower platen 24. If only one of the members is driven, the non-drive member will be rotated due to the frictional transmission of torque by the blank during the pulley forming operation.

A rough roll forming member 58 and a finish roll forming member 60 are arranged to be simultaneously advanced at substantially right angles toward the longitudinal axis of the pulley blank, and to cooperate with the members 38, 40 in the pulley forming operation. The roll forming members 58 and 60 are respectively mounted on slide assemblies 62 and 64. The assembly 62 is slidingly engaged with a base plate 66 by means of an interlocking slide channel 66a (FIG. 3) therein. The plate 66 is fixed to the lower platen 24. The assembly 64 is similarly mounted for sliding movement by means of a base plate 68 which is also secured to the lower platen and includes a slide channel 680. As set forth in greater detail below, each of the assemblies is normally biased to a retracted position clear of the pulley blank as shown in FIGS. 1 through 3.

The slide assemblies are respectively cam actuated by cam arms 70 and 72 which are rigidly secured to the upper platen by means of bolts 74. The cam arms 70 and 72 cooperate with associated cam heel blocks 76 and 78 which provide laterally confining bearing surfaces for the cam arms. The cam heel blocks are secured to the lower platen 24 by means of bolts 80.

In addition to providing bearing surfaces for the associated cam arms, the heel blocks are also respectively employed in the biasing of the adjacent slide assembly to its retracted position. Specifically, the slide assembly 62 is threadedly engaged with bolts 82 which extend through the heel block 76 with clearance. The bolts 82 and the slide assembly are resiliently biased to the left as shown in FIGS. 1 through 3, into a retracted position, by means of springs 84 which are compressively retained between the bolt head and the outward surface of the heel block. The retractive movement of the assembly is limited by its interlocking engagement with the base plate 66 and, more particularly, the length of the slide channel 66a. The slide assembly 64 is similarly biased by identical bolts and spring members, and its retractive movement is limited by the slide channel 68a.

The cam arm includes a camming surface 70a arranged to work against a pivot arm 86 having a camming surface 86a. As explained in greater detail below, the pivot arm 86 is connected to the assembly 62 by means of a mounting pin 88 and it is arranged to pivot in a clockwise direction as shown in FIG. 2.

The cam arm 72 is similarly provided with a camming surface 72a arranged to work directly against the surface 64a of the slide assembly 64. The ssociated camming surfaces are arranged to uniformly drive the slide assemblies toward the longitudinal axis A of the blank.

The rough forming roll 58 is carried by a fixed shaft 90 extending from the slide assembly 62. The forming roll 58 is mounted for rotation about the shaft 90 by means of a collar 92. The roll is also axially movable relative to the shaft, and it is resiliently biased to an unloaded position by means of a compression spring 94 working between the collar and the slide assembly.

The forming roll 60 is similarly mounted on shaft 96 extending from the slide assembly 64, and it is also mounted for rotative movement about the shaft by means of a collar 98. The forming roll 60 is also axially movable relative to the shaft 96, and it is biased to its unloaded position by means of compression springs 100 and 102.

OPERATION In the pulley forming operation, a pulley blank, such as the blank 20, is positioned on the lower die member 48 as shown in FIGS. 1 through 3. During the loading of the apparatus, the press is in its open position andthe platens as well as the axially movable members are axially spaced apart. Further, the slide assemblies are biased to their laterally retracted positions by springs 84.

The pilot pin 54 is received within the bore 36 of the blank, and the terminating edge 34 of the sidewall of the blank is confined by a ring member 104. It should be appreciated that the pilot pin may be omitted and that the blank will be retained in a stable position by means of the ring member 104. After the blank has been loaded in the apparatus, one or both of the members 38, 40 may be rotatably driven in order to establish relative rotation between the blank and the forming roll members.

Referring to FIG. 4, the apparatus is illustrated in the initial stages of the pulley forming operation. The member 38 has been brought into crushing engagement with the blank by the closing movement of the upper platen 22. The slide assemblies 62 and 64 are simultaneously advanced toward the blank by the camming action of their associated camming arms 70 and 72. The apparatus is arranged so that the initial contact of the upper die member 44 with the closed end 30 of the blank substantially coincides with the engagement of the sidewall 32 of the blank by the forming rolls, and more particularly, the engagement of the rough roll 58 since it is moved slightly in advance of the finish roll 60.

As indicated above, the rough roll 58 is moved toward the longitudinal axis of the blank slightly in advance of the finish roll 60 which is captively maintained in the groove as it is being formed. Accordingly, during the initial stages of the pulley forming operation, the rough roll is engaged in a working operation in which the pulley groove is progressively formed and the finish roll is engaged with the partially formed pulley groove in an idling, but not working, operation. The idling operation of the finish roll within the partially formed pulley groove expedites the pulley forming operation by substantially maintaining the finish roll in a radially advanced and axially aligned position ready to commence its working operation.

The rough roll 58 may be moved in advance of the finish roll by simply arranging the cam arm 70 to initiate movement of the slide assembly 62 just prior to the movement of the slide assembly 64. Alternatively, the retracted positions of the slide assemblies 62 and 64 on relative diameters of the rolls 58 and 60 can be varied with appropriate adjustment of the respective cam actuated movements thereof. Further, the cam angle of the finish roll drive may be arranged to initially move the finish roll at a slightly slower lateral advance rate than the rough roll, and upon interchange at a slightly greater rate.

As shown in F IG. 4, the forming rolls 58 and 60 are axially disposed so as to initially engage the sidewall 32 of the blank adjacent the open end thereof. Accordingly, as the pulley groove is progressively formed the metal is rolled predominantly from the portion of the sidewall adjacent the closed end of the blank, and the edge 34 adjacent the open end of the blank remains in engagement with the lower die.

Referring to FIG. 5, the apparatus is shown just after the completion of the rough roll forming operation with the rough forming roll 58 in a disengaged, retracted position. The cam arm 70 has completed the advance of the rough forming roll into the sidewall of the blank, and the cam surface 70a has moved out of engagement with the surface 86a of the pivot arm 86. Upon disengagement of the cam surfaces, the pivot arm 86 steps over the lower portion of the cam arm 70 and the slide assembly is resiliently biased to its retracted position by the springs 84.

As shown in FIG. a, the pulley groove includes a doubled wall 106 defined by the adjacent portions of the closed end and the sidewall 32 of the blank. The doubled wall 106 is connected through a root 108 of the partially formed pulley groove to an opposed single wall 110.

As the rough roll 58 is removed from working engagement within the partially formed pulley groove, the finish roll 60 is simultaneously disposed in a working operation within the partially formed pulley groove. Specifically, the slide assembly 64 is slightly advanced toward the longitudinal axis A so as to move the finish roll from its captive, idling position within the partially formed pulley groove to a working position in which its outer peripheral extremities are contiguous with the root of the groove. The finish roll is then further laterally advanced in a working operation to move the root of the groove radially inwardly to the ultimate root diameter of the pulley groove being formed.

Referring to FIG. 6, the apparatus is shown just prior to the completion of the pulley forming operation with the axially movable members and the finish roll at their final apposition in which they define the ultimate cross section of the pulley being formed. At this point, the associated camming surfaces 72a and 64a have moved out of engagement and the lateral advance of the finish roll 60 is completed. The finish roll and the slide assembly are maintained in a laterally stationary position by virtue of engagement between the axially aligned surfaces 72b of the cam arm 72 and 64b of the assembly 64.

Referring to FIG. 6a, the details of the ultimate cross section of the pulley being formed are shown. The opposed doubled wall 106 and the single wall 110 have been axially crushed against the surface of the finish roll 60 and the root 108 has been advanced to the desired diameter. The upper die pad 46 and the lower die pad 50 are contiguously disposed adjacent opposite sides of the closed end 30 of the pulley blank which now provides the central portion of the pulley.

Preferably, the foregoing portion of the pulley forming operation is completed prior to the time any yielding motion of the lower axially movable member 40 and the lower platen 24 has occurred. In other words, the air spring 28 is adjusted to provide a resisting force greater than the ram pressure required to complete the axial deformation of the blank. Accordingly, the lost motion dwell of the pulley forming apparatus is intended to commence after the axially movable die members and the finish roll have been moved to their final apposition. Thus, during the dwell the axially movable members are translated as a unit along with the finish roll which travels within the pulley groove to perform the truing operation and assure the balance and concentricity of the pulley.

Referring to FIG. 7, the pulley forming apparatus is shown at the end of the dwell movement with the axially movable members and the finish roll still in engagement with the now completely formed pulley. During the dwell period, the further advance of the ram plate 16 and the camming arm 72 does not result in the further lateral displacement of the slide assembly 64 as indicated above, but merely results in the disposition of the surfaces 72b and 64b in a contiguous relationship. The downward translation of the movable members as a unit is permitted by the yielding movement of the air spring. Specifically, the support rods 26 are moved downwardly through the bolster plate 18 into a compressed position of the air spring and the platen 24 is permitted to bottom out against the bolster plate so as to provide about one inch of dwell travel.

At the end of the ram stroke or the full extension of the ram 15, the retum movement of the ram begins and the platens and axially movable members are moved to an open position by their following movement to permit the removal of the finished pulley. The lower platen as well as the slide assemblies and the member 40 are returned to their unloading position by the air spring upon removal of the ram pressure.

During the return movement of the platen, the lower portion of the cam arm engages the pivot arm 86 causing it to rotate in a clockwise direction as shown in FIG. 7. Further, the compression spring prevents the finish roll from rapidly returning to its retracted axial position upon the initial separation of the members 38 and 40. Accordingly, the roll 60 is smoothly withdrawn from the pulley groove without marring or otherwise damaging the surfaces of the pulley walls.

In the preferred operation of the apparatus, the pulley blank is completely deformed prior to the beginning of the lost motion dwell. However, it should be appreciated that one of the advantages of providing such a dwell is that it is not necessary to precisely synchronize the completion of the ram stroke or the closing movement of the axially movable members with the lateral advance of the finish roll. For example, the lateral advance of the finish roll and the movement of the root to its ultimate diameter may be completed after the dwell period has commenced. In this case, the dwell period and lost motion travel are sufficient to permit the late radial advance of the root to the desired diameter and allow a truing operation to be thereafter performed during the remaining portion of the dwell period.

It should also be appreciated that the axial crushing or closing movement of the members 38 and 40 may also be completed after the dwell period has begun. For example, if the wall thickness of the blank was slightly over gauge, the ram pressure required to complete the axial deformation of the blank may also be slightly greater than the force necessary to initially bias the air spring. In this instance, the dwell period would begin and when the force required to further bias the air spring increases to a value equal to that necessary to complete the axial deformation of the over gauge blank, it would temporarily be interrupted bythe completion of the axial crushing of the blank. Upon completion of the axial crushing, the dwell commences once again and the axially movable members further translate together as a unit with the finish roll within the groove performing the truing operation.

The elimination of the need to precisely synchronize the arrival of the forming members at their final apposition is believed to significantly contribute to the achievement of the high cycle times which result upon the use of the pulley forming apparatus in punch presses to provide pulley forming machines. The high cycle rate is of course complimented by the precise and immediate positioning of the forming rolls throughout the pulley forming operation. In this regard, the apparatus and method of the present invention directly utilize the closing movement of the press to perform the axial crushing and rolling operations in a mechanically efficient manner.

The invention is not restricted to the slavish imitation of each and every detail set forth above. Obviously techniques and devices may be devised which change, eliminate or add certain specific details without departing from the scope of the invention.

We claim:

1. Apparatus for forminga pulley having a pulley groove of given cross section defined by pulley wall means connected through the root of the groove from a pulley blank in the form of a sheet metal cup having an axially extending cup wall and a longitudinal axis, comprising axially movable members for engaging said blank adjacent opposed axial ends thereof, means to axially advance at least one of said axially movable members toward the other to a final apposition at which they define a die cavity corresponding to portions of said pulley, roll die means comprising first and second forming rolls, means to establish relative rotation between said pulley blank and said forming rolls, roll die moving means to substantially simultaneously advance said forming rolls toward said longitudinal axis while said axially movable members are moved toward said final apposition, said roll die moving means including means to progressively move said first forming roll in advance of said second forming roll to deform said cup wall in a working operation and partially form said pulley groove while maintaining said second forming roll disposed within said partially formed pulley groove in an idling operation, and disengagement means for removing said first forming roll from working engagement with the partially formed pulley groove prior to the disposition of said axially movable members in said final apposition, said roll die moving means including means to further advance said second forming roll in a working operation toward said longitudinal axis to an imaginary circle having a diameter equal to the root diameter of the desired pulley groove to cause said second forming roll and said axially movable members at their final apposition to completely define said die cavity.

2. Apparatus as set forth in claim 1 wherein said roll die means include slide assemblies carrying said forming rolls and said roll die moving means comprise cam means arranged to engage said slide assemblies and ad vance said forming rolls toward said longitudinal axis.

3. Apparatus as set forth in claim 2 wherein said forming rolls are axially, movably mounted on said slide assemblies to provide axial movement of said forming rolls within the pulley groove being formed as said axially movable mebers move to said final apposi- IIOII.

4. Apparatus as set forth in claim 3 wherein said forming rolls are resiliently mounted on shafts carried by said slide assemblies to provide said axial movement thereof.

5. Apparatus as set forth in claim 1 wherein said means to axially advance at least one of said axially movable members includes dwell means for providing a dwell period during which said axially movable members move as a unit in said final apposition together with said second forming roll.

6. Apparatus for forming a pulley having a pulley groove of given cross section defined by outwardly flaring wall portions connected through the root of the groove from a pulley blank in the form of a sheet metal cup having an axially extending cylindrical sidewall and a longitudinal axis comprising axially movable die means for axially crushing said cup upon the closing movement thereof relative to said cup, roll die means for simultaneously applying radially inwardly directed, rolling pressure progressively around the circumference of said cylindrical sidewall to form a groove having outwardly flaring wall portions connected through a root, die moving means for advancing said die means toward a final apposition at which they cooperate to define a die cavity corresponding to the desired cross section of the pulley, dwell means for providing a dwell period during which said axially movable die means move as a unit in said final apposition with said roll die means.

7. Apparatus as set forth in claim 6 wherein said dwell means comprise mounting means for axially, yieldingly supporting said axially movable die means.

8. Apparatus as set forth in claim 7 wherein said mounting means comprise an air spring.

9. A method of forming a pulley having a pulley groove of preselected cross section defined by outwardly flaring wall portions connected through the root of the groove from a pulley blank in the form of a sheet metal cup having an axially extending cup wall and a longitudinal axis comprising the steps of providing first and second forming rolls for applying radially inwardly directed, rolling pressure progressively around the circumference of said cup wall in working operations, applying axial pressure to said cup while simultaneously applying rolling pressure to said cup wall by moving said first forming roll in advance of said second forming roll to progressively deform said cup wall in a working operation and partially fonn said pulley groove while maintaining said second forming roll disposed within said pulley groove in an idling operation as it is being formed, disengaging said first forming roll from working engagement withthe partially formed pulley groove, and advancing said second forming roll into a working operation and toward said longitudinal axis to an imaginary circle having a diameter equal to the desired root diameter to form a pulley groove having outwardly flaring wall portions connected through a root of desired diameter.

10. A method as set forth in claim 9 wherein the steps of disengaging said first forming roll and advancing said second forming roll into a working operation are performed substantially simultaneously.

11. A method as set forth in claim 10 including the steps of disengaging said second forming roll after said desired root diameter is established and terminating the axial crushing of said cup after said outwardly flaring wall portions have been deformed to said preselected cross section against said second forming roll.

12. A method as set forth in claim 10 wherein the step of applying axial pressure to said cup includes axially crushing the cup between axially closing die members and providing a lost motion dwell during which said die members are translated as a unit together with said'second forming roll in their final forming positions relative to said cup.

13. A method of forming a pulley including a pulley groove having a predetermined cross section defined by outwardly flaring wall portions connected through the root of the groove from a pulley blank comprising the steps of:

l. providing a cup shaped, metal pulley blank having a cylindrical sidewall and a longitudinal axis;

2. axially crushing said blank between closing die means while simultaneously radially inwardly advancing the root of the groove being formed by applying rolling pressure around the circumference of said cylindrical sidewall to progressively form a groove having outwardly flaring wall portions connected through the root thereof,

3. advancing said closing die means as a unit in a single direction to provide a lost motion dwell in the closing movement of said die means relative to said blank,

4. completing the axial crushing and radially inwardly advance of the root prior to the end of said lost motion dwell to ultimately provide a pulley groove having a predetermined cross section defined by said flaring wall portions connected through a root of desired diameter.

14. A method as set forth in claim 13 wherein the steps of completing the axial crushing and radially inwardly advance of the root are performed prior to said lost motion dwell.

15. A method as set forth in claim 13 wherein the step of advancing said closing die means as a unit in a single direction is provided by the axially, yielding movement of at least one of said die means. 

1. Apparatus for forming a pulley having a pulley groove of given cross section defined by pulley wall means connected through the root of the groove from a pulley blank in the form of a sheet metal cup having an axially extending cup wall and a longitudinal axis, comprising axially movable members for engaging said blank adjacent opposed axial ends thereof, means to axially advance at least one of said axially movable members toward the other to a final apposition at which they define a die cavity corresponding to portions of said pulley, roll die means comprising first and second forming rolls, means to establish relative rotation between said pulley blank and said forming rolls, roll die moving means to substantially simultaneously advance said forming rolls toward said longitudinal axis while said axially movable members are moved toward said final apposition, said roll die moving means including means to progressively move said first forming roll in advance of said second forming roll to deform said cup wall in a working operation and partially form said pulley groove while maintaining said second forming roll disposed within said partially formed pulley groove in an idling operation, and disengagement means for removing said first forming roll from working engagement with the partially formed pulley groove prior to the disposition of said axially movable members in said final apposition, said roll die moving means including means to further advance said second forming roll in a working operation toward said longitudinal axis to an imaginary circle having a diameter equal to the root diameter of the desired pulley groove to cause said second forming roll and said axially movable members at their final apposition to completely define said die cavity.
 2. Apparatus as set forth in claim 1 wherein said roll die means include slide assemblies carrying said forming rolls and said roll die moving means comprise cam means arranged to engage said slide assemblies and advance said forming rolls toward said longitudinal axis.
 2. axially crushing said blank between closing die means while simultaneously radially inwardly advancing the root of the groove being formed by applying rolling pressure around the circumference of said cylindrical sidewall to progressively form a groove having outwardly flaring wall portions connected through the root thereof,
 3. advancing said closing die means as a unit in a single direction to provide a lost motion dwell in the closing movement of said die means relative to said blank,
 3. Apparatus as set forth in claim 2 wherein said forming rolls are axially, movably mounted on said slide assemblies to provide axial movement of said forming rolls within the pulley groove being formed as said axially movable mebers move to said final apposition.
 4. Apparatus as set forth in claim 3 wherein said forming rolls are resiliently mounted on shafts carried by said slide assemblies to provide said axial movement thereof.
 4. completing the axial crushing and radially inwardly advance of the root prior to the end of said lost motion dwell to ultimately provide a pulley groove having a predetermined cross section defined by said flaring wall portions connected through a root of desired diameter.
 5. Apparatus as set forth in claim 1 wherein said means to axially advance at least one of said axially movable members includes dwell means for providing a dwell period during which said axially movable members move as a unit in said final apposition together with said second forming roll.
 6. Apparatus for forming a pulley having a pulley groove of given cross section defined by outwardly flaring wall portions connected through the root of the groove from a pulley blank in the form of a sheet metal cup having an axially extending cylindrical sidewall and a longitudinal axis comprising axially movable die means for axially crushing said cup upon the closing movement thereof relative to said cup, roll die means for simultaneously applying radially inwardly directed, rolling pressure progressively around the circumference of said cylindrical sidewall to form a groove having outwardly flaring wall portions connected through a root, die moving means for advancing said die means toward a final apposition at which they cooperate to define a die cavity corresponding to the desired cross section of the pulley, dwell means for providing a dwell period during which said axially movable die means move as a unit in said final apposition with said roll die means.
 7. Apparatus as set forth in claim 6 wherein said dwell means comprise mounting means for axially, yieldingly supporTing said axially movable die means.
 8. Apparatus as set forth in claim 7 wherein said mounting means comprise an air spring.
 9. A method of forming a pulley having a pulley groove of preselected cross section defined by outwardly flaring wall portions connected through the root of the groove from a pulley blank in the form of a sheet metal cup having an axially extending cup wall and a longitudinal axis comprising the steps of providing first and second forming rolls for applying radially inwardly directed, rolling pressure progressively around the circumference of said cup wall in working operations, applying axial pressure to said cup while simultaneously applying rolling pressure to said cup wall by moving said first forming roll in advance of said second forming roll to progressively deform said cup wall in a working operation and partially form said pulley groove while maintaining said second forming roll disposed within said pulley groove in an idling operation as it is being formed, disengaging said first forming roll from working engagement with the partially formed pulley groove, and advancing said second forming roll into a working operation and toward said longitudinal axis to an imaginary circle having a diameter equal to the desired root diameter to form a pulley groove having outwardly flaring wall portions connected through a root of desired diameter.
 10. A method as set forth in claim 9 wherein the steps of disengaging said first forming roll and advancing said second forming roll into a working operation are performed substantially simultaneously.
 11. A method as set forth in claim 10 including the steps of disengaging said second forming roll after said desired root diameter is established and terminating the axial crushing of said cup after said outwardly flaring wall portions have been deformed to said preselected cross section against said second forming roll.
 12. A method as set forth in claim 10 wherein the step of applying axial pressure to said cup includes axially crushing the cup between axially closing die members and providing a lost motion dwell during which said die members are translated as a unit together with said second forming roll in their final forming positions relative to said cup.
 13. A method of forming a pulley including a pulley groove having a predetermined cross section defined by outwardly flaring wall portions connected through the root of the groove from a pulley blank comprising the steps of:
 14. A method as set forth in claim 13 wherein the steps of completing the axial crushing and radially inwardly advance of the root are performed prior to said lost motion dwell.
 15. A method as set forth in claim 13 wherein the step of advancing said closing die means as a unit in a single direction is provided by the axially, yielding movement of at least one of said die means. 